Mode-locking of anisotropic Tm,Ho:GdScO₃ laser delivering 57-fs pulses at 2078 nm

Area of Science:

• Laser physics
• Materials science
• Solid-state optics

Background:

• Mode-locked lasers are crucial for generating ultrashort optical pulses.
• The 2-micrometer spectral range is important for various applications, including spectroscopy and medical treatments.
• Developing new laser materials is key to advancing laser performance.

Purpose of the Study:

• To investigate the potential of a novel Tm,Ho-codoped orthorhombic perovskite crystal for ultrashort pulse generation.
• To characterize the performance of a SESAM mode-locked bulk laser utilizing this new crystal.
• To explore ultrashort pulse generation across different crystallographic axes.

Main Methods:

• Fabrication of a SESAM mode-locked bulk laser incorporating a Tm,Ho-codoped GdScO3 crystal.
• Characterization of laser output, including pulse duration, wavelength, average power, and repetition rate.
• Measurement of pulse properties along different crystallographic polarization axes (E//a, E//b, E//c).

Main Results:

• Generation of sub-100 femtosecond (fs) pulses in the 2-micrometer spectral range.
• Achieved a shortest pulse duration of 57 fs at 2078 nm with polarization along the E//b axis.
• Obtained an average power of 202 mW at a repetition rate of 86.6 MHz without additional dispersion elements.
• Demonstrated polarization-dependent pulse characteristics along all three crystallographic axes.

Conclusions:

• The anisotropic Tm,Ho-codoped GdScO3 crystal is a promising material for generating ultrashort pulses around 2 micrometers.
• The SESAM mode-locked laser design enables efficient ultrashort pulse generation with potential for further optimization.
• This work opens avenues for novel laser sources in the mid-infrared region.